As a continually, slowly escalating dose efficacy study, newer data obtained from the epileptic patients on flupirtine indicates that at dosages higher then 680mg/day, disposition of flupirtine may reveal non-linearity. We have now finished 9 patients who were evaluated at least 3 times - twice following multiple dosing to study any time dependent effects on kinetics. Estimation of fraction absorbed at higher doses suggests that non-linearity is not associated with drug absorption. Further analyses is presently underway to characterize drug's disposition in these patients and compare data and results with those obtained from other studies in other populations.